DNS Setting up DNS ns1/ns2 nameservers ?

if you already have 3rd party dns, you do not need to set ns1/ns2 all you need is www and @ A records pointing to server IP and then domain updated with your 3rd party dns providers name servers

if you want vanity @ns1/ns2 your domain name servers like at Domains - Domain name DNS setup on local NSD server | Centmin Mod Community you need to create those nameservers in your panel first so ask your dns provider about vanity nameservers as you have that wrong, creating vanity nameservers is NOT an A record, it's separately done and depends on dns control panel/provider.

 

with domain registrars like namecheap.com, namesilo.com and internet.bs at least when you register a domain, you also get free dns hosting, so like your dns control panel, these domain registrars provide you with their own nameservers i.e. ns1.domainregistrarprovided.com and you just add to your domain's dns settings that provided ns1 where your screenshot above had ns1 for and ip and ns1 would be provided by your domain registrar or dns manager.

If you want vanity ns1.yourdomain need to create the nameservers yourself

i.e.

• for namesilo at Manage Name Servers
• at guide part 1 section at Nginx Vhost & NSD DNS Setup - Centmin Mod - Menu based Nginx installer for CentOS servers = Namecheap.com Knowledgebase • How do I register personal nameservers for my domain?
• Godaddy Setting Nameservers for Your Domain Names | GoDaddy Help | GoDaddy Support
• DNSMadeeasy Vanity DNS - Welcome to DNS Made Easy TutorialsWelcome to DNS Made Easy Tutorials

Your domain registrar and dns control panel with that registrar should have their own instructions you need to ask them about.

Splitting these posts to DNS forums now too